From: Spudboy100@aol.com
Date: Mon Jun 03 2002 - 23:14:26 MDT
Source: Penn State
(http://www.psu.edu/)
Date Posted: Monday, June 03, 2002
Web Address: http://www.sciencedaily.com/releases/2002/06/020603071300.htm
PENN STATE ENGINEERS BOOST HYDROGEN PRODUCTION FROM FERMENTATION
The cars powered by hydrogen fuel cells that the Bush Administration has
partnered with the Detroit Big Three automakers to develop could eventually
be pulling up to wastewater treatment plants for fill-ups, say Penn State
environmental engineers.
Dr. Bruce Logan, professor of environmental engineering, and his research
group have shown they can boost hydrogen production 43 percent by using a
continuous hydrogen release fermentation process. He explains that by using
certain industrial wastewater as feedstock, the approach offers an abundant,
"green," local source for hydrogen and potentially makes it a cheaper fuel
than gasoline.
"Continuous fermentation is not hard to do and the high volumes of gas
produced make it a potential source of supply for a wide variety of fuel cell
applications besides cars and buses, including home power generation and the
micro-fuel cells being developed for consumer products such as laptops, cell
phones, smoke alarms, and calculators," Logan adds.
Logan and Dr. Sang-Eun Oh, postdoctoral fellow; Dr. In S. Kim, professor of
environmental engineering, Kwang-Ju Institute of Science and Technology, and
Steven Van Ginkel, doctoral candidate, are the authors of a paper,
"Biological Hydrogen Production Measured in Batch Anaerobic Respirometers,"
published in the current (May) issue of the journal, Environmental Science
and Technology. The paper details the group's experiments comparing the
standard fermentation method, in which hydrogen is released from the
processing vessels intermittently, with a method in which the gas is released
continuously.
In the Penn State experiments, fermentation was conducted with bacteria from
ordinary garden soil. The soil, collected from local farmland, was heat
treated to kill hydrogen-consuming bacteria. While the heat treatment also
kills non-hydrogen producing soil bacteria, it leaves hydrogen-producing
bacteria in a dormant spore form that revives as soon as it is put in
suitable conditions.
The researchers mixed the heat-treated soil with individual samples of
glucose, sucrose, cellulose, lactate, potato starch and molasses.
Fermentation of both glucose and sucrose with the heat-treated soil under
slightly acidic conditions in the absence of oxygen produced high
concentrations of hydrogen gas. Releasing the gas continuously during glucose
processing resulted in 43 percent more hydrogen than when the gas was
released intermittently.
Logan notes that wastewater from confectioners, canneries, sugar refineries,
and other industries are rich in glucose and sucrose. "The conversion of the
chemical energy in these sugars to electricity in fuel cells via hydrogen
gas, provides a method for wastewater treatment and renewable energy
production in one step. The greatest savings at treatment plants may result
from reducing costs for aerators since aeration is the major operational
expense at most wastewater treatment plants," says the Penn State researcher.
In addition, methane could also be generated via the same process and from
the same materials to provide an additional source of clean energy for fuel
cells.
Logan says, "Both hydrogen and methane production via fermentation could save
money spent on aeration while at the same time making a wastewater treatment
plant into a local power plant."
Van Ginkel notes that, "Generating hydrogen by fermentation is not new. Batch
fermentation was used during World War II to produce industrial solvents for
ammunition production. Small amounts of hydrogen produced early in the
fermentation process were not recovered.
However, the industry later switched to steam reformation of petroleum to
produce these industrial solvents when oil was cheap.
"Now, that oil has become more expensive, more efficient ways to generate
hydrogen, for example the continuous fermentation processing method, may help
us cross the barrier to realizing hydrogen's promise as the fuel of the
future," he adds.
The research was supported by a grant from the National Science Foundation.
Dr. Oh's participation was supported by Brain Korea 21 program funding which
supports sending Korean graduate students abroad for study and research.
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